Fix sign in token and warning emails failed to send in some cases (#17589)

app/mailers/user_mailer.rb

@@ -169,7 +169,7 @@ class UserMailer < Devise::Mailer
     I18n.with_locale(@resource.locale || I18n.default_locale) do
       mail to: @resource.email,
            subject: I18n.t("user_mailer.warning.subject.#{@warning.action}", acct: "@#{user.account.local_username_and_domain}"),
-           reply_to: Setting.site_contact_email
+           reply_to: ENV['SMTP_REPLY_TO']
     end
   end
 
@@ -206,7 +206,7 @@ class UserMailer < Devise::Mailer
     I18n.with_locale(@resource.locale || I18n.default_locale) do
       mail to: @resource.email,
            subject: I18n.t('user_mailer.sign_in_token.subject'),
-           reply_to: Setting.site_contact_email
+           reply_to: ENV['SMTP_REPLY_TO']
     end
   end
 end